Electrical components having an enhanced reliability are needed for high-availability and/or critical systems such as web or transaction servers. Additional testing may be performed on components such as board assemblies, semiconductor chips, and memory modules. Often this additional testing is performed at an elevated temperature. Such environmental testing is also known as burn-in.
Weak components often fail earlier at elevated temperatures than at normal temperatures. Poor solder connections on boards or modules can break at higher temperatures, and thermal expansion can loosen poorly seated components. Other manufacturing defects that do not cause immediate failures can create failures that appear after many hours of normal operation at normal temperatures, or after just a few hours at elevated temperatures. Thus elevated-temperature testing can screen for weak components that might later fail in the field, enhancing reliability.
Electronic systems such as servers and personal computers (PCs) use dynamic-random-access memory (DRAM) chips mounted on small, removable memory modules. Older single-inline memory modules (SIMMs) have been replaced with dual-inline memory modules (DIMMs), 184-pin RIMMs (Rambus inline memory modules) and 184-pin DDR (double data rate) DIMMs. New kinds of memory modules continue to be introduced, such as 240-pin DDR2 (double data rate 2) DIMMs.
The memory-module industry is quite cost sensitive. Testing costs are significant, especially for higher-density modules. Specialized, high-speed electronic test equipment is expensive, and the greater number of memory cells on high-speed memory modules increases the time spent on the tester, increasing test costs.
Burn-in testing can be quite expensive, as each module may have to remain at an elevated temperature in a specialized burn-in tester for many hours or even days. Ideally, the memory module is exercised electronically during the burn-in testing, rather than simply be stored at the high temperature and later tested. Operating the memory module at higher frequencies increases internal heating within the DRAM chips, providing more realistic and thorough testing, increasing reliability.
Exercising the memory modules at higher frequencies is difficult, especially when the modules are within a burn-in oven or heated test chamber. Cables or wires that connect an external test-pattern generator or other test equipment to the memory modules within the oven can be long, severely limiting the frequency of operation.
The parent applications disclosed a memory-module burn-in test system that has removable pattern-generator boards. The pattern-generator boards are separated by an insulated backplane from a heat chamber that contains the memory modules under test.
What is desired is improved hot-air flow in such a burn-in test system that tests memory modules at elevated temperatures. An air-flow and heating system is desired for the test system with the removable pattern-generator boards that are insulated from the heat chamber.